Low-cost rifle scope display adapter

ABSTRACT

Embodiments of the invention(s) described herein enable the display of information (e.g., information related to aiming and/or target selection and/or other information) through the use of a rifle scope display adapter (RDA) that can be coupled to and/or placed in proximity to an existing rifle scope. This information, which is viewable through the eyepiece of the rifle scope, can come from a spotter and/or other information source. The RDA may utilize a polarized transmissive-reflective optical element to enable light generated by the RDA to be reflected into the objective of the rifle scope, as well as light from a scene viewable by the rifle scope to be transmitted through the polarized transmissive-reflective optical element to the objective.

CROSS-REFERENCES TO RELATED APPLICATIONS

The present application is a continuation-in-part of U.S. patentapplication Ser. No. 15/784,673, filed Oct. 16, 2017, entitled “RIFLESCOPE TARGETING DISPLAY ADAPTER MOUNT,” which is a continuation of U.S.patent application Ser. No. 15/093,237, filed on Apr. 7, 2016, (whichissued Oct. 17, 2017, as U.S. Pat. No. 9,791,244), entitled “RIFLE SCOPETARGETING DISPLAY ADAPTER MOUNT,” which claims the benefit under 35 USC119(e) of U.S. Provisional Application No. 62/144,218, filed on Apr. 7,2015, entitled “MULTI-USE RIFLE SCOPE PROJECTED DISPLAY MOUNTINGTECHNIQUE,” which is incorporated herein by reference. U.S. patentapplication Ser. No. 15/093,237 is also a continuation-in-part of U.S.patent application Ser. No. 15/079,851, filed on Mar. 24, 2016, entitled“RIFLE SCOPE TARGETING DISPLAY ADAPTER,” which is incorporated herein byreference.

U.S. patent application Ser. No. 15/079,851 claims the benefit under 35USC 119(e) of the following U.S. Provisional Applications: U.S.Provisional Application No. 62/137,585, filed on Mar. 24, 2015, entitled“SMART COMPACT RIFLE SCOPE DISPLAY ADAPTER (RDA)”; U.S. ProvisionalApplication No. 62/138,893, filed on Mar. 26, 2015, entitled “RIFLESCOPE WITH INTEGRATED TARGETING DISPLAY”; and U.S. ProvisionalApplication No. 62/144,218, filed on Apr. 7, 2015, entitled “MULTI-USERIFLE SCOPE PROJECTED DISPLAY MOUNTING TECHNIQUE.” Each of these U.S.Provisional Applications listed above is incorporated herein byreference.

U.S. patent application Ser. No. 15/079,851 is also acontinuation-in-part of U.S. patent application Ser. No. 14/543,761,filed on Nov. 17, 2014, (which issued May 10, 2016 as U.S. Pat. No.9,335,124), which is incorporated herein by reference.

BACKGROUND

Aspects of the disclosure relate in general to the display of aiming,target selection and/or other information through a rifle scope.

Current military tactics call for combat snipers to work in closecoordination with a spotter as part of a sniper team. The spotterprovides protection and situational awareness for the sniper, since thesniper must devote substantial energy and attention to positioning thesniper rifle for an effective shot. Oftentimes, the spotter uses atargeting computer that is designed to provide aiming informationappropriate for the sniper rifle being used. Some targeting computersprovide the observer with a video feed of the target environment andcompute aim point adjustments based on the wind, distance to target,target movement and the ballistic characteristics of the rifle beingused.

When utilizing such a targeting computer, the spotter typically providesthe sniper with a verbal description of the intended target as well as avertical and horizontal adjustment factor. The sniper then manuallymoves the scope of the sniper rifle to reflect the vertical andhorizontal adjustment factor. Once the scope is adjusted, the sniper cansight the target with the scope reticle for an accurate shot. However,this process requires the sniper to remove his/her hands from the firingposition, which may cause the rifle to shift on the rifle support. Thisprocess may also require the sniper to momentarily take their eyes offthe target in order to make manual adjustments. Communicating targetinginformation verbally between the spotter and the sniper can alsogenerate noise and distractions that can give away the sniper'sposition.

BRIEF SUMMARY

Embodiments of the invention(s) described herein enable the display ofinformation (e.g., information related to aiming and/or target selectionand/or other information) through the use of a rifle scope displayadapter (RDA) that can be coupled to and/or placed in proximity to anexisting rifle scope. This information, which is viewable through theeyepiece of the rifle scope, can come from a spotter and/or otherinformation source. The RDA may utilize a polarizedtransmissive-reflective optical element to enable light generated by theRDA to be reflected into the objective of the rifle scope, as well aslight from a scene viewable by the rifle scope to be transmitted throughthe polarized transmissive-reflective optical element to the objective.

An example rifle scope display adapter, according to the description,comprises a body coupleable with a rifle scope and having a display unitdisposed in a casing and an optical subassembly disposed in the casingthat includes a lens and a reflective element. The optical subassemblyis configured to direct light from the display unit toward a polarizedtransmissive-reflective optical element. The polarizedtransmissive-reflective optical element is coupled with the casing suchthat, when the body of the rifle scope display adapter is coupled withthe rifle scope, the polarized transmissive-reflective optical elementis disposed in front of an objective lens of the rifle scope in a mannerto reflect the light from the display unit toward the objective lens ofthe rifle scope, and transmit other light incident to the polarizedtransmissive-reflective optical element and traveling toward theobjective lens of the rifle scope.

Embodiments of the rifle scope display adapter may comprise one or moreof the following features. The polarized transmissive-reflective opticalelement may comprise a polarized window. The polarizedtransmissive-reflective optical element may be configured to, when thebody of the rifle scope display adapter is coupled with the rifle scope,occupy substantially all of the field of view of the rifle scope. Thedisplay unit may comprise a liquid crystal on silicon (LCOS). Theoptical subassembly may further comprise a light-emitting element, apolarizing element configured to polarize light emitted by thelight-emitting element, and a polarized beam splitter, where thepolarized beam splitter is configured to reflect the polarized lighttowards the LCOS and transmit light reflected by the LCOS toward thereflective element, the light reflected by the LCOS comprising the lightfrom the display unit. The rifle scope display adapter may furthercomprise a diffuser disposed between a light-emitting element and thepolarized beam splitter, where the diffuser is operable to diffuse lightemitted by the light-emitting element. The lens of the opticalsubassembly may comprise a movable telephoto lens. The rifle scopedisplay adapter may further comprise a polarized coating on only aportion of a surface of the polarized transmissive-reflective opticalelement. An area of the portion of the surface comprises less than 20%of the total area of the surface.

An example method of directing light from a display unit toward anobjective lens of a rifle scope, according to the description, comprisescausing the display unit to display an image, and using an opticalsubassembly to direct light from the display unit toward a polarizedtransmissive-reflective optical element, where the optical subassemblyincludes a lens and a reflective element. The method further comprisespositioning the polarized transmissive-reflective optical element suchthat the polarized transmissive-reflective optical element is disposedin front of the objective lens of the rifle scope in a manner to reflectthe light from the display toward the objective lens of the rifle scope,and transmit other light incident on the polarizedtransmissive-reflective optical element traveling toward the objectivelens of the rifle scope.

Embodiments of the method may comprise one or more the followingfeatures. The polarized transmissive-reflective optical element maycomprise a polarized window. The polarized transmissive-reflectiveoptical element may be configured to, when the rifle scope displayadapter is coupled with the rifle scope, occupy substantially all of thefield of view of the rifle scope. The display unit may comprise a liquidcrystal on silicon (LCOS). The method may further comprise causing alight-emitting element to emit light, polarizing the light emitted bythe light-emitting element, and using a polarized beam splitterconfigured to reflect the polarized light towards the LCOS, and transmitlight reflected by the LCOS toward the reflective element, where thelight reflected by the LCOS comprises the light from the display unit.The method may further comprise diffusing light emitted by thelight-emitting element. The lens of the optical subassembly may comprisea movable telephoto lens. The polarized transmissive-reflective opticalelement may be configured to reflect the light from the display unitusing a polarized coating on only a portion of a surface of thepolarized transmissive-reflective optical element. An area of theportion of the surface may comprise less than 20% of the total area ofthe surface.

Another example rifle scope display adapter, according to thedescription, comprises a display unit disposed in a casing and anoptical subassembly disposed in the casing and including an adjustablelens and a reflective element. The optical subassembly is configured todirect light from the display unit toward a polarizedtransmissive-reflective optical element. The polarizedtransmissive-reflective optical element is coupled with the casing suchthat, when the rifle scope display adapter is positioned for use, thepolarized transmissive-reflective optical element is disposed in frontof an objective lens of the rifle scope in a manner to reflect the lightfrom the display unit toward the objective lens of the rifle scope andtransmit other light incident to the polarized transmissive-reflectiveoptical element traveling toward the objective lens of the rifle scope.In some embodiments of the rifle scope display adapter, the polarizedtransmissive-reflective optical element may comprise a polarized window.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of this invention, reference is nowmade to the following detailed description of the embodiments asillustrated in the accompanying drawings, in which like referencedesignations represent like features throughout the several views andwherein:

FIG. 1A is a block diagram of an example rifle scope display adapter.

FIG. 1B is a perspective diagram of an example rifle scope displayadapter.

FIG. 1C is an oblique, left-side view of an example rifle scope displayadapter.

FIG. 1D is a frontal view of an example rifle scope display adapter.

FIG. 2A is a block diagram of an example rifle scope display adapterdepicted relative to components of a rifle scope to which the adapter isaffixed.

FIG. 2B is a perspective diagram depicting a rifle scope to which anexample rifle scope display adapter is affixed.

FIG. 2C is block diagram of a rifle scope display adapter that shows amagnified view of certain adapter components, and depicts a path oflight relative to these components.

FIG. 2D is a block diagram that shows an example light path relative tocomponents of a rifle scope display adapter and components of a riflescope to which the adapter is affixed.

FIG. 3 is a diagram showing example paths of light rays within a riflescope display adapter.

FIG. 4 illustrates one example of a view provided by a traditional riflescope.

FIG. 5A illustrates an RDA control and a view through a rifle scope withan uncalibrated RDA, according to some embodiments.

FIG. 5B illustrates a rotationally aligned virtual crosshairs that needsto be vertically and/or horizontally aligned, according to someembodiments.

FIG. 5C illustrates a rotationally and vertically aligned virtualcrosshairs that needs to be horizontally aligned, according to someembodiments.

FIG. 5D illustrates a set of virtual crosshairs that are rotationally,vertically, and horizontally aligned with the crosshairs of the riflescope, according to some embodiments.

FIG. 6A illustrates an RDA control and a view through a rifle scope forcalibrating the zoom function of an RDA, according to some embodiments.

FIG. 6B illustrates an example of a fully calibrated RDA, according tosome embodiments.

FIG. 7A illustrates virtual symbols for gauging the precision of awindage calculation relative to a target, according to some embodiments.

FIG. 7B illustrates the visual elements of FIG. 7A after they havegraphically converged, according to some embodiments.

FIG. 8A illustrates the chevron-style visual elements relative to thesilhouette in FIGS. 7A-7B, according to some embodiments.

FIG. 8B illustrates a visual element in the form of a circle surroundingthe silhouette, according to some embodiments.

FIG. 9 illustrates a view of the target area through an RDA, accordingto some embodiments.

FIG. 10 illustrates a plurality of different targeting reticles that canbe selected by the shooter during the configuration phase for the RDA,according to some embodiments.

FIG. 11A illustrates a block diagram of an electrical system for an RDA,according to some embodiments.

FIG. 11B illustrates a block diagram of a second electrical system foran RDA, according to some embodiments.

FIG. 12 illustrates a flowchart of a method for displaying firingsolutions using a display adapter that is configured to mount to a frameof a rifle scope, according to some embodiments.

FIGS. 13A-13D illustrate various views of one embodiment of an RDAassembly, according to some embodiments.

FIG. 14 illustrates an outside view and an inside view of the innerring, according to some embodiments.

FIG. 15 illustrates an outside view and an inside view of the spacer,according to some embodiments.

FIG. 16 illustrates a collet, according to some embodiments.

FIG. 17 illustrates an outside view and an inside view of an outer ring,according to some embodiments.

FIG. 18 illustrates an RDA mount assembly for a large scope body,according to some embodiments.

FIG. 19 illustrates an RDA mount assembly for a smaller scope body,according to some embodiments.

FIG. 20 illustrates a flowchart of a method for securing an RDA to ascope body, according to some embodiments.

FIG. 21 is a perspective view of an RDA having a polarized window,according to an embodiment.

FIG. 22 is a diagram of the embodiment of an RDA of FIG. 21, attached toa rifle scope, and showing light paths in a manner similar to FIGS. 2C,and 2D.

FIG. 23 is a ray tracing diagram showing example paths of light rayswithin an example embodiment of an RDA having a polarized window.

In the appended figures, similar components and/or features may have thesame reference label. Further, various components of the same type maybe distinguished by following the reference label by a dash and a secondlabel that distinguishes among the similar components. If only the firstreference label is used in the specification, the description isapplicable to any or all of the similar components having the same firstreference label irrespective of the second reference label.

DETAILED DESCRIPTION OF THE INVENTION

Several illustrative embodiments of a rifle scope display adapter willnow be described with respect to the accompanying drawings, which form apart of this disclosure. While particular rifle scope display adapterimplementations and embodiments are described below, other embodimentsand alternative designs may be made without departing from the scope ofthe disclosure or the spirit of the appended claims.

As used herein, the term “transmissive-reflective optical element”refers to an optical element that is capable of both reflecting lightand transmitting light. This includes the transmissive light bar andpolarized window described in the embodiments provided herein. A personof ordinary skill in the art will recognize that other optical elements,therefore, may be considered “transmissive-reflective optical elements”.Such elements may further be polarized to enable, for example, moreeffective reflection of polarized light. The use of polarized coatings,for example, may enable such elements to be polarized.

According to some embodiments, a lightweight, compact rifle scopedisplay adapter can be configured to be securely affixed to a riflescope in front of the scope's objective lens. When attached to a riflescope, the “rifle scope display adapter” (hereinafter also referred tointerchangeably as a “display adapter” and/or an “adapter”) can beoperated to supplement the rifle scope view of the target by displayingaim point and/or trajectory information computed by a ballistic computerfor a selected target. Specifically, the rifle scope display adapter canprovide aim point information in the form of illuminated symbology thatoverlays the target view seen through the eyepiece of the scope. Theadapter provides the symbology in such a way that it overlays the viewprovided by the rifle scope optics, without impeding a sniper's view ofthe target environment. In a simple form, the adapter enables aconventional scope to be operated as a “red dot” scope without anymodification other than attachment of the adapter to the scope to theend of the rifle scope.

The rifle scope display adapter can be configured as a small andlightweight unit that can be tightly fastened to the front end ofconventional magnifying rifle scopes without requiring any scopemodification. A mechanical mounting fixture coupled to the adapterallows the adapter to be quickly attached to and removed from the riflescope without equipment such as wrenches or screwdrivers. Additionallyor alternatively, the rifle scope display adapter may include componentsfor mounting the adapter immediately in front of a rifle scope objectivelens in such a way that the adapter is coupled to and supported by therifle itself, without being affixed to the scope. This disclosureprimarily describes and illustrates embodiments of the rifle scopedisplay adapter that include components for affixing the adapterdirectly to a rifle scope. However, in view of these descriptions anddrawings, the design of alternative rifle scope adapter embodiments thatfacilitate direct mounting to a rifle would be readily apparent to oneof ordinary skill in the art, and are therefore within the scope of thisdisclosure.

The rifle scope display adapter may include optical elements, processingcircuitry, mounting hardware, electrical connectors, and cabling. Therifle scope display adapter may also include light emitting circuitry.The illumination source of the symbology that overlays the image viewedthrough the rifle scope may be considered light emitting circuitry,according to some embodiments. The light emitting circuitry providesfront lighting of a liquid crystal on silicon element that includesnumerous reflective pixels, each of which can reflect incident light ina manner that can be varied by an electrical control signal. Within therifle scope display adapter, the location, intensity, color and shape ofaim point symbology and/or video images is controlled by electricsignals that vary the reflection provided by individual liquid crystalon silicon (LCOS) reflective elements. By activating a particularcombination of reflective elements while other reflective elements areinactive, the adapter projects and directionally controls light forilluminating a symbol or video image viewable through the scope. Therifle scope optics focus this projected light in such a way that itappears as overlaying the image of the target or other scene viewedthrough the scope.

While mounted in front of or attached to the rifle scope, the displayadapter can be communicatively coupled to a targeting or ballisticcomputer wirelessly or by way of a connecting cable. The display adaptercan be coupled to the computer regardless of whether the computer isalso mounted on the rifle or detached and independently manipulated by aspotter or working in cooperation with a sniper.

The communicative coupling enables the display adapter to receive aimpoint and trajectory information computed by a ballistic computer. Theaim point information may include an aim point displacement relative tothe rifle scope reticle. In this case, processing circuitry within theadapter controls a combination of LCOS optical reflective elements sothat light reflected from the LCOS, when focused at the rifle scopeeyepiece, will be seen to reflect the specified offset relative to thereticle.

Alternatively or additionally, the optical system may receive raw imagedata through the connecting cable. The image data may consist of raw orcompressed pixilation data for the display of symbology, video, or stillimages. The processing circuitry then sets control signals for the LCOSreflective elements so that each signal reflects the corresponding pixelvalue in the data.

The rifle scope display adapter may project an aim point indicatorsymbol so that it is observed as a small illuminated dot that overlaysthe natural image of the target. In this way, the shooter can move therifle to place the projected aim point indicator on the target insteadof the aim point of the rifle scope. By moving the rifle in this way,the shooter can compensate for the computed effect of windage and/orbullet drop without adjusting the scope, looking away from the scopeimage, changing his/her grip on the rifle, and/or manipulating aballistic computer.

FIG. 1A is a generalized block diagram showing an examplaryconfiguration of certain light emitting components, optical components,and circuitry in the rifle scope display adapter 40, according to someembodiments. FIG. 1A is intended to be viewed in conjunction with FIGS.1B-1D, which will be described together with FIG. 1A. FIG. 1B is aperspective diagram of the rifle scope display adapter 40 from a vantagepoint to the front and left of the adapter. FIG. 1C is an oblique viewof the rifle scope adapter 40 as seen from the left side of the adapter.FIG. 1D is a frontal view of the adapter 40. FIGS. 1A-1D depict therifle scope display adapter 40 in a standalone condition in which it isnot attached to a rifle scope or other rifle mounting point.

In FIG. 1A, certain components are depicted within a casing 44. Thecasing 44, which is also visible in FIGS. 1B-1D, may surround andenclose these components on all sides, thereby providing protection fromthe elements, as well as some degree of protection from optical noiseand peripheral light that could otherwise interfere with the quality ofthe images and symbols projected when the display adapter is affixed toa rifle scope.

The components depicted within the casing 44 (which are explicitly shownin FIG. 1A) include processing circuitry 41, an LED 52, LCOS 39,diffuser (not shown in FIG. 1A), polarizer 53, polarized beam splitter51 (referred to hereinafter as a “first polarized beam splitter” todifferentiate it from another similar component), moving telephoto lens61 and reflective element 54. The moving telephoto lens 61 providesparallax adjustment. Through movement of a knob 94 mounted external tothe casing 44 and visible in FIGS. 1B-1D, a shooter can position thetelephoto lens 61 as needed to prevent parallax from affecting the viewof the target seen through a rifle scope. A button interface 96explicitly depicted in FIGS. 1B and 1C provides an interface to theprocessing circuitry 41 so that display brightness, display mode, andother display settings can be adjusted.

The image processing circuitry 41 is also used to control, amongst otherthings, the light emitted by a light emitting diode (LED) 52. The LED 52emits white light that is the source of the illumination used to projectaim point symbology and video images when the display adapter 40 isattached to a rifle scope. Light emitted by the LED 52 is reflected bythe (LCOS) 39. The LCOS 39 includes several thousand reflective crystalelements, each of which is controlled by way of an electrical signalgenerated by the processing circuitry 41. The processing circuitry 41controls the display of symbology or video images by using theseelectrical signals to cause reflections to occur at the LCOS in such away that the reflected light is focused by the rifle scope optics,causing the desired to appear.

In FIG. 1A, these electrical signals are represented by the solid arrowbetween the processing circuitry 41 and the LCOS 39. The processingcircuitry 41 includes a connection port 92 at which a cable can beattached to connect the processing circuitry 41 to an external ballisticcomputer, targeting, and/or video generating device. The processingcircuitry 41 processes aim point and trajectory information, video data,and/or image data received through a cable attached to connection port92.

In FIGS. 1B-1D an intermediate cable 93 is depicted as being connectedto the processing circuitry 41 at the connection port 92. Theintermediate cable 93 includes a female connecting port through which anelectrical connection between a ballistic computer and the processingcircuitry 41 of the display adapter 40 may be established. Otherembodiments may additionally or alternatively include wirelesscommunication means, such as a radio frequency (RF) transceiver,antenna, and/or the like.

The processing circuitry 41 may be designed to access aim point andtrajectory information in the form of raw data representative of an aimpoint symbol display location. The display location may be specified asan offset from a rifle scope reticle. For the purposes of thisdisclosure, the rifle scope “reticle” refers to fixed crosshairs thatare positioned at the center of a rifle scope image, or, more generally,to the center of the image seen through a scope. The reticle of therifle scope may be permanently etched into a glass element of the riflescope, and may be contrasted with the projected targeting imagedisplayed by the rifle scope display adapter. The aim point andtrajectory information may alternatively be in the form of pixel datarepresenting an image having an aim point symbol positioned tocompensate for computed windage and bullet drop.

FIG. 1A also depicts other optical components external to the casing 44,several of which are also depicted in FIGS. 1B-1D. These componentsinclude a transmissive light bar 55, an additional polarized beamsplitter 56 (hereinafter “second polarized beam splitter”), a sphericalmirror 58 and a quarter-wave plate 57. As can be seen in FIG. 1B, thelight bar 55 diametrically traverses an annulus 60 on which the casing44 is mounted. As will be illustrated in other drawings provided herein,the annulus 60 is configured to extend forward of a rifle scope'sobjective lens when the display adapter 40 is affixed to the scope. Whenthe display adapter 40 is attached to a rifle scope, an aperture in theannulus 60 allows light from the scene to pass unimpeded to theobjective lens of the scope. In this way, the optics of the scope canfocus an image of the target at the eyepiece.

A series of arrows in three dimensions is also shown in FIG. 1A. Thisseries of arrows is intended to provide a directional reference systemthat is consistent across multiple different viewing angles manifestedin the drawings provided herein. These arrows (X, Y, and Z) arepresented throughout the drawings in a manner that is consistent withrespect to the components of the rifle scope display adapter, despitethe difference in viewing angles from one drawing to the next.

FIG. 2A is a block diagram that shows the rifle scope display adapter 40in a condition in which it is affixed to a rifle scope 43. Other thanfor the fact that FIG. 2A shows the adapter 40 components relative tocomponents of the rifle scope 43 to which the adapter 40 is affixed, thediagram of the display adapter 40 in FIG. 2A is similar to the displayadapter in FIG. 1A. FIG. 2B, which is meant to be viewed in conjunctionwith FIG. 2A, is a perspective diagram of the display adapter 40 of FIG.2A and the rifle scope 43 to which it is affixed. FIG. 2B represents aview of display adapter 40 and rifle scope 43 as seen from slightly tothe front and left of the rifle scope 43.

As shown in FIGS. 2A and 2B, the rifle scope 43 includes an objectivelens 75 and additional magnifying lenses 80. The rifle scope 43 alsoincludes an eyepiece 76 through which an image of a target or scene canbe viewed. Moreover, symbols, images and video can be projected by thedisplay adapter 40 and focused by the rifle scope 43 optics so as to bevisible at the eyepiece 76. The display adapter 40 can provide theseprojections so that they overlay the view of the target or occupy theentire eyepiece 76.

The rifle scope display adapter 40 shown in FIGS. 2A and 2B is affixedto the rifle scope 43 with the annulus 60 of the adapter 40 surroundingthe sides of the rifle scope 43 at the target end of the rifle scope 43.A portion of the annulus 60 extends slightly forward of the objectivelens 75, in the direction of the target (x-direction, as shown by thedashed arrow). Also, the lightbar 55 traversers the aperture of theannulus 60 at a point slightly forward of the objective lens 75. It isimportant to note that several display adapter components previouslydepicted in FIG. 1A are also shown in FIG. 2A, but are too small to belabeled.

FIG. 2C includes the depiction of the rifle scope display adapter 40affixed to a rifle scope 43, as previously seen in FIGS. 2A and 2B. FIG.2C also shows a magnified view of the rifle scope display adapter 40components enclosed by the casing 44, as well as a first portion of apath of light emitted by the LED 52 during illumination of an aim pointsymbol projected by the adapter 40 and focused at the rifle scopeeyepiece 76. A second part of this path will be shown in FIG. 2D.

The depiction of the path of light in FIGS. 2C and 2D is highlygeneralized and is not intended to show angles of incidence, reflectionand refraction. As such, these drawings should be understood asexhibiting only an approximate path of light relative to the variouscomponents of the rifle scope display adapter 40, as well as depictingcertain adapter components that reflect the light within the casing 44and certain components that transmit the light.

For example, FIG. 2C depicts that after light is emitted by the LED 52,it is transmitted and polarized by the polarizer 53. As a result of thepolarization of the light that occurs at the polarizer 53, the light isreflected towards the LCOS 39 at the first polarized beam splitter 51.While the processing circuitry 41 controls the reflective pixel elementsof the LCOS 39, various active pixel elements reflect the light back inthe direction of the first polarized beam splitter 51.

After being reflected at the LCOS 39, the light is transmitted by boththe first polarized beam splitter 51 and the moving telephoto lens 61.The reflective element 54 then reflects the light into the light bar 55.

FIG. 2D provides a generalized illustration of a second portion of thepath of light illustrated in FIG. 2C. The second portion of the path oflight begins at reflective element 54, at which point the light entersthe light bar 55. Thus FIG. 2D is intended to be viewed in combinationwith FIG. 2C, which depicts the path of the light ray prior to its exitfrom the casing 44 of the display adapter 40. As shown in FIG. 2D, thelight enters the light bar 55 after being reflected at reflectiveelement 54, is transmitted at the second polarizing beam splitter 56 andis reflected by the spherical mirror 58.

The light undergoes a polarity reversal imparted by the quarter-waveplate 57 and is then incident on the second polarizing beam splitter 56.The second polarizing beam splitter 56 reflects the light towards theobjective lens 75 of the rifle scope. The light is incident on theobjective lens 75 near the center of the lens, while light from thescene is incident on the objective lens 75 between the center andperiphery of the lens. The magnifying 80 lenses of the rifle scope thenrefract and focus the light projected by the display adapter 40, as wellas the light emanating from the scene. In this way, the light projectedby the display adapter 40 is brought into focus as a symbol or imagevisible at the eyepiece 76 of the rifle scope. Simultaneously, the lightemanating from the scene is brought into focus at the eyepiece 76. Inthis way, a shooter is able to see a magnified view of the target withan overlaid aim point symbol or other image while looking through therifle scope 43.

FIG. 3 is a schematic diagram showing the path of light rays in therifle scope display adapter 40 during projection of a symbol or imagevisible through a rifle scope. In FIG. 3, depiction of the light emittedby the LED and the reflection of this light towards the LCOS 39 isomitted in order to avoid unnecessary complication of the drawing.Rather, the rays shown in the drawing are intended to illustrate thepath of light only after its reflection at the LCOS 39. Additionally,the light path through the rifle scope is omitted in FIG. 3.

Although not shown, the LED 52 emits light towards a polarizing beamsplitter 51 that is angled 45 degrees relative to the path of the light.Prior to reaching the first polarizing beam splitter 51, the light canbe polarized by the polarizer 53. Optionally, the light may be diffusedby a diffuser prior to reaching the first polarizing beam splitter 51(e.g., the diffuser is disposed between the LED 52 and the polarizingbeam splitter 51), before or after the polarizer 53. In some embodimentsthe polarizer 53 may also act as a diffuser.

Also, a wire grid polarizer (not shown) is used to polarize the light insuch a way that it will be reflected at the first polarizing beamsplitter 51. Because of the polarity of the light incident on the firstpolarizing beam splitter 51, the beam splitter reflects the lighttowards the LCOS 39 (leftwards, as viewed in FIG. 3).

The processing circuitry 41 generates electrical control signals thatcause a combination of LCOS reflective pixel elements to reflect theincident light. The LCOS 39 also reverses the polarity of the light thatit reflects. The light reflected by the LCOS 39 is reflected backtowards the first polarizing beam splitter 51, where it is transmittedas a result of the polarity reversal imparted by the LCOS 39.

After being transmitted by the first polarized beam splitter 51, thelight propagates towards a moving telephoto lens 61 that providesparallax adjustment. The light is divergently refracted by the telephotolens 61 in a manner that provides compensation sufficient to preventparallax from affecting the rifle scope view.

Subsequent to being transmitted by the telephoto lens 61, the light isincident on a reflective element 54 that is disposed at an angle that isapproximately 45 degrees from parallel to the path of the light. Thereflection of the light by the reflective element 54 causes anapproximately 90 degree change in direction of the light. Followingreflection, the light propagates through light bar 55. The light bar 55may be shaped as a rectangular prism formed of a transmissive materialthat surrounds a second polarized beam splitter 56.

The second polarized beam splitter 56 is disposed within the light bar55, and is approximately centered with respect to the circular aperture(not shown in FIG. 3) of the annulus. By being centered with respect tothe circular aperture, the second polarizing beam splitter 56 isdisposed so that it will coincide with an extended optical axis (notexplicitly labeled) of the rifle scope 43 to which the adapter 40 isaffixed. That is, the second polarizing beam splitter 56 will bedisposed directly in front of the center of the rifle scope objectivelens (not shown in FIG. 3).

As a result of the polarity of the light when reflected at reflectiveelement 54, the light is transmitted by the second polarizing beamsplitter 56 and is incident on the spherical mirror 58 disposed at theend of the light bar 55 opposite the reflective element 54. Thespherical mirror 58 reflects the light towards the second polarizingbeam splitter 56 and reverses the polarity of the light. Also, aquarter-wave plate 57 is disposed between the second polarizing beamsplitter 56 and the spherical mirror 58. The quarter-wave plate reversesthe polarity of the light.

As a result of the polarity reversal imparted by the quarter-wave plate57, the second polarizing beam splitter 56 reflects the light, causing a90 degree change in direction. As can be seen in FIG. 3, the light raysare effectively collimated by the reflection that occurs at thespherical mirror 58 and second polarizing beam splitter 56. Thesecollimated light rays are then incident at the objective lens of therifle scope (not shown), which transmits and refracts the rays towardsthe optical eyepiece in the manner depicted in FIG. 2D.

Rifle Scope Display

FIG. 4 illustrates one example of a view 402 provided by a traditionalrifle scope. The view 402 shows a view of a long range target area 410as seen through the eyepiece of a standalone magnifying rifle scopeprior to installation of the rifle scope display adapter describedherein. Shooting accurately at long ranges is not as simple as lining upa crosshair 408 with a target in the target area 410. For example, theenvironment between the rifle scope and the target area 410 may includestrong crosswinds. Additionally, long-range shots need to take theeffect of gravity into account, which causes a shot to drop between therifle and the target area 410. A magnetic heading of the rifle may alsoaffect long-range shots. A shot taken under these circumstances woulddrop and move to the right because of the strong left crosswind andeffect of gravity over the lengthy distance to the target area 410.

Thus, to accurately hit targets in the target area 410 when using thestandalone rifle scope shown in FIG. 4, a shooter would need toapproximate an aimpoint above and to the left of the target. The shootercould approximate the aimpoint based on an estimation of the strength ofthe left cross-wind and the distance to the target area 410. The shootercould then use the aimpoint by manually aligning the crosshair above andto the left of the target. However, this methodology is very imprecise.The shooter could achieve better results by mechanically adjusting therifle scope downwards and to the right using manual windage andelevation knobs that are included in most modern rifle scopes. However,making these mechanical adjustments can delay the shot and complicatethe aiming process because the shooter's hands must be removed from theweapon, and may require the shooter to remove their eyes from the riflescope, thus taking their eyes off the target. Also, the mechanicaladjustment can only be as precise as the shooter's mental estimation ofthe necessary wind and elevation compensation.

Alternatively, the shooter or an assisting spotter could use a ballisticcomputer in conjunction with a laser rangefinder to compute acompensatory scope adjustment. The shooter would then mechanicallyadjust the rifle scope downwards and to the right by an amountequivalent to the computed adjustment. The adjustment to the scope wouldcause the rifle to actually be pointed above and to the left of thetarget, while the crosshair is seen as visually aligned with the targetto the shooter's eye. Although this methodology is precise, it stillrequires that the shooter's hands be removed from the weapon and theshooter's eyes to be removed from the target prior to the shot beingtaken.

In addition to illustrating the view 402 of the target area 410 providedby the traditional rifle scope, FIG. 4 also illustrates markings thatmay be included as part of a rifle scope. For example, a crosshair 408may be provided at the center of the rifle scope to indicate abore-sighted aimpoint. Windage tick marks 404 may be used to help theshooter adjust for windage calculations/estimations. Elevation tickmarks 406 may be provided to help the shooter adjust for bullet drop dueto gravity. The crosshair 408, the windage tick marks 404, and/or theelevation tick marks 406 may be permanently etched into a glass elementof the rifle scope, or alternatively may be implemented using visiblewire elements inside the rifle scope. In either case, the crosshair 408,the windage tick marks 404, and/or the elevation tick marks 406 of therifle scope may be permanently affixed to the rifle scope, and may beadjusted by windage and/or elevation knobs coupled to the outside frameof the rifle scope. These permanent markings in the rifle scope may bereferred to herein as “visual rifle scope elements.”

In order to provide a more integrated and accurate method forcompensating for long-range effects of a rifle shot, the embodimentsdescribed herein for a rifle scope display adapter (RDA) may projectinformation and/or symbols onto the optical elements of the RDA suchthat the information and/or symbols are clearly and immediately visibleto the shooter through the rifle scope. As will be described below,windage, elevation, azimuth angles, tilt angles, and/or rotation(“cant”) angles can be automatically measured in real time and displayedthrough the RDA to the shooter. A ballistic computer can use each ofthese measurements as inputs to generate a targeting solution that movesa virtual targeting reticle to a compensated location. The shooter canalign the compensated location of the virtual targeting reticle throughthe rifle scope with the target in the target area for an accurate shotwithout removing his/her eyes from the target and without manuallyadjusting the windage/elevation knobs of the rifle scope.

In some embodiments, the RDA can be mechanically attached to the end ofthe rifle scope opposite the shooter's eyepiece. As described in detailabove, the optical components of the RDA can display text and/orsymbology through the optics of the rifle scope such that they arevisible to the shooter. However, in order to ensure that the displayedsymbology is properly scaled and aligned with the visual rifle scopeelements, a calibration procedure can first be performed on the RDA asfollows.

FIG. 5A illustrates an RDA control 502 and a view 510 through a riflescope with an uncalibrated RDA, according to some embodiments. The RDAcontrol 502 may be physically positioned on the side of the RDA asdepicted in FIG. 1B (96). The RDA control 502 may include a button 504with a plus symbol, a button 508 with a minus symbol, and a button 506with a square symbol. Each of these buttons 504, 506, 508 can be used toadjust the text and/or symbols projected by the RDA during thecalibration procedure. As used herein, visual elements projected by theRDA through the rifle scope may be referred to as “virtual” elements orsymbols as opposed to the visual rifle scope elements that are alsovisible to the shooter through the rifle scope.

Because the RDA connects to the cylindrical end of the rifle scope, itis likely that a virtual crosshairs 514 will need to be rotated in orderto align rotationally, horizontally, and/or vertically with thecrosshairs 516 of the rifle scope. Instead of requiring the shooter tophysically rotate the RDA on the end of the scope to align the virtualcrosshairs 514, the rotational alignment can be performed electronicallyusing the RDA control 502. For example, pressing button 504 can rotatethe virtual crosshairs 514 counterclockwise, while pressing button 508can rotate the visual crosshairs 514 clockwise. Button 506 can bepressed when the rotational alignment of the virtual crosshairs 514 iscomplete. Graphically, the RDA can display a set of coordinates 512 thatshows a position of the virtual crosshairs during the calibrationprocedure.

It will be understood that the buttons of the RDA control 502 are merelyexemplary and not meant to be limiting. Other embodiments may usealternative types of controls, such as alpha-numeric keypads, touchscreens, wireless controls, and/or the like.

FIG. 5B illustrates a rotationally aligned virtual crosshairs 514 thatneed to be vertically and/or horizontally aligned, according to someembodiments. By pressing button 506, the calibration procedure can nextmove to a vertical alignment phase. The functions of button 504 andbutton 508 can change from rotating the virtual crosshairs 514clockwise/counterclockwise, and instead can shift the virtual crosshairs514 vertically up/down. By pressing button 506, the shooter can indicatethat the vertical alignment is complete. FIG. 5C illustratesrotationally and vertically aligned virtual crosshairs 514 that need tobe horizontally aligned, according to some embodiments. Similar to theprocess described above, pressing 504 and button 508 can horizontallyshift the virtual crosshairs 514 to the left/right. FIG. 5D illustratesa set of virtual crosshairs 514 that are rotationally, vertically, andhorizontally aligned with the crosshairs 516 of the rifle scope.

The entire calibration procedure can be performed by visually aligningthe virtual crosshair hairs 514 with the permanent crosshairs 516 of therifle scope. Thus, the RDA can be quickly attached to the end of therifle scope without complicated or precise installation procedures.Instead, the positioning of the RDA can be performed electronicallywithout special tooling and without extensive training. Furthermore,this calibration procedure allows the RDA to be used on a wide varietyof rifle scopes without requiring specific software and/or hardware toaccommodate each type of crosshair that may be available.

FIG. 6A illustrates an RDA control 502 and a view 510 through a riflescope for calibrating the zoom function of an RDA, according to someembodiments. In order to accurately display adjustments to windage andelevation, the zoom factor of the rifle scope must be aligned with thezoom factor of the symbols and text displayed by the RDA. After aligningthe virtual crosshairs 514 using the process described above, the zoomfactor may be calibrated by aligning the tick marks 602 of the RDA withthe tick marks 606 of the rifle scope. During this procedure, button 504may be used to magnify the RDA display, while button 508 may be used tozoom out the RDA display. Again, the tick marks 602 of the RDA can bealigned with the tick marks 606 of the rifle scope visually without theneed of special equipment. When the tick marks are aligned, the shootercan press button 506 to end this phase of the calibration procedure.FIG. 6B illustrates an example of a fully calibrated RDA, where thevirtual crosshairs 514 are aligned with the crosshairs of the riflescope, and the zoom factor of the RDA is aligned with the zoom factor ofthe rifle scope.

Once the RDA is calibrated with a properly bore-sighted rifle scope, thevirtual crosshairs of the RDA can later be used to calibrate thecrosshairs of the rifle scope. There is some drift or hysteresis in thewindage and elevation adjustment knobs of many rifle scopes. Thephysical shock of each rifle shot may cause some physical movement ofthe crosshairs due to this inaccuracy inherent in mechanical adjustmentknobs. Normally, shooters would have to re-bore sight their rifle afterevery 10 to 20 shots. Instead, the shooter can follow the reverseprocedure described above, and align the crosshairs of the rifle scopewith the displayed virtual crosshairs of the RDA through manualadjustment.

FIG. 7A illustrates virtual symbols for gauging the precision of awindage calculation relative to a target, according to some embodiments.A silhouette 702 can be displayed to illustrate the approximatedimensions of a target at a particular distance. The silhouette 702 canbe scaled based on the zoom factor of the RDA as well as the distance tothe target. For example, at longer distances, the silhouette 702 can berendered smaller in order to approximate the size of the target at thegreater distance when viewed through the rifle scope.

A set of visual elements 704 can be used to graphically indicate aprecision with which a windage calculation has been determined. Variouselectronic devices are commercially available that can be used tostatistically estimate a windage calculation. Light can be transmittedfrom the device at the target and reflected back to a precision camerato detect scattering of the reflected light. As the scattered light isstatistically sampled over time, algorithms for estimating a directionand velocity of wind between the measurement device and the target canconverge to a precise value. Typically, the statistical convergence ofthese algorithms takes between 2 s and 10 s.

The visual elements 704 can be used to graphically indicate to theshooter the degree to which the windage measurement has converged. Inthe example of FIG. 7A, the visual elements 704 include opposingchevrons that move towards the silhouette 702 as the windage calculationconverges. When the calculation begins, the visual elements 704 may bespread relatively wide, leaving the silhouette 702 alone in the middleof the RDA view. As the windage calculation converges, the visualelements 704 will gradually move inwards until they close in on thesilhouette 702. FIG. 7B illustrates the visual elements 704 of FIG. 7Aafter they have graphically converged on the silhouette 702, indicatingthat the windage measurement has also converged.

The visual elements 704 of FIGS. 7A-7B are merely exemplary and notmeant to be limiting. Any other type of graphical elements may be usedto illustrate convergence of a windage calculation. FIG. 8A illustratesthe chevron-style visual elements 804 relative to the silhouette 802described above in FIGS. 7A-7B. In another example, FIG. 8B illustratesa visual element 808 in the form of a circle surrounding the silhouette806. As the windage calculation converges, the visual element 808 canshrink until it is relatively close to the silhouette 806.

FIG. 9 illustrates a view of the target area 410 through an RDA,according to some embodiments. As shown in FIG. 9, the RDA may beoperated by a shooter in an aimpoint assistance mode. Although notdepicted in FIG. 9, the RDA may be communicatively connected to aballistic computer (e.g., via wired and/or wireless communication). Theballistic computer may be operated by a spotter working in the shooter'svicinity, or maybe integrated into a system on the rifle scope itself.In some embodiments, a ballistic computer may also operate on theprocessor of the RDA locally.

In one configuration, the ballistic computer can receive inputs forenvironmental sensors and compute a firing solution. Inputs to theballistic computer may include a target range as determined by laserrangefinder, a magnetic bearing or azimuth angle (e.g., X° Northwest, Y°South, etc.), a tilt angle of the rifle, a cant angle of the rifle,and/or a wind measurement. Each of these inputs may be provided byexternal systems, or may be provided by sensors integrated onto the RDAitself. Regardless of whether these measurements are provided by the RDAitself or by an external system, the measurement results can bedisplayed in real time on the RDA for the shooter. For example, FIG. 9illustrates a range measurement 902, an azimuth angle measurement 904(to be used to compensate for the Coriolis effect of the Earth'srotation), an altitude angle measurement 906, and/or a cant anglemeasurement 908 that are displayed in real time for the shooter. As theshooter moves or rotates the rifle, the measurements 902, 904, 906, and908 can be dynamically updated on the RDA such that the change isimmediately visible to the shooter.

In some embodiments, the altitude angle measurement 906 and the cantangle measurement 908 can be provided from the RDA as inputs to theballistic computer to calculate a targeting solution. In otherembodiments, the display of altitude angle measurement 906 and the cantangle measurement 908 can be merely informational for the shooter. Inresponse, the shooter can rotate or adjust the altitude angle of therifle until they are close to 0.0 as shown in real-time on the RDAdisplay.

The ballistic algorithms used to calculate a firing solution are beyondthe scope of this disclosure. Algorithms capable of calculating firingsolutions may be commercially available from companies such as AppliedBallistics® and/or Kestrel®. A wind measurement sensor is described inthe commonly assigned U.S. patent application Ser. No. 14/696,004 filedon Apr. 24, 2015, which is incorporated herein by reference.

The output of the firing solution may be comprised of a windageadjustment and an elevation adjustment to be applied by the shooter tothe rifle scope. Like the input measurements 902, 904, 906, and 908, thefiring solution can also be displayed in real time as it is calculatedthrough the RDA. For example, an elevation adjustment 914 can bedisplayed, as well as a windage adjustment 916. The units for theelevation adjustment 914 and the windage adjustment 916 can be setduring the calibration phase according to the units used by the riflescope itself. For example, the rifle scope in FIG. 9 uses “mils” (MRADS,or milliradians), while other rifle scopes may instead use Minutes ofAngle (MOA).

The range and windage measurements may be calculated using algorithmsbased on a laser being reflected from a target. Because there is somecalculation time involved, visual indicators may be provided by the RDAto indicate to the shooter when those calculations are complete. Forexample, an “R” symbol 912 may be dynamically displayed to indicate thatthe range calculation has been completed. Similarly, a “W” symbol 910may be dynamically displayed to indicate that the windage calculationhas been completed. Before these calculations are completed, the Rsymbol 912 and/or the W symbol 910 may be absent from the display. Thesemeasurements may be displayed in addition to the chevron symbols 922and/or the silhouette 918 described above to indicate the degree towhich the displayed windage measurement has been able to converge.

In traditional rifle scopes, the shooter would be required to manuallyadjust the windage and/or elevation knobs on the rifle scope in order toreposition the permanent crosshairs of the rifle scope. Alternatively,the shooter could reposition the rifle using the tick-mark scale on therifle scope in order to estimate a correct shot. Either of thesesolutions led to inaccuracy or forced the shooter to take his/her handsoff the rifle in order to make manual adjustments.

In contrast, the embodiments described herein can use the firingsolution calculated by the ballistic computer and automatically displaya targeting reticle 924 that is correctly positioned according to thecalculated windage and elevation adjustments. For example, if the treein the target area 410 is the desired target, the shooter can aim therifle such that targeting reticle 924 is in line with the target. Thiscan be done without making any manual adjustments and without takingeyes off the target. Furthermore, instead of estimating how far therifle needs to be raised or shifted horizontally, the shooter can simplyposition the targeting reticle 924 over the target. The targetingreticle 924 can be repositioned each time a new windage/rangecalculation is completed. Therefore, by using the targeting reticle 924to target the rifle, the shooter can automatically incorporate alltargeting solution calculations into the targeting reticle 924 for anaccurate shot.

In some embodiments, the wind sensor and/or the laser rangefinder may beincorporated into the RDA or into a unit attached to the rifle or riflescope. In these embodiments, the center of the rifle scope crosshairs(e.g., the silhouette 918) would first need to be pointed at the at thetarget so that a range/windage measurement to be taken. Once therange/windage calculations are completed, the targeting reticle 924 willappear, and the shooter can reposition the rifle such that the targetingreticle 924 is on the target.

As was the case with the graphical elements for indicating convergenceof the windage calculation algorithm, the actual visual representationof the targeting reticle can include a number of different embodiments.FIG. 10 illustrates a plurality of different targeting reticles 1002that can be selected by the shooter during the configuration phase forthe RDA.

FIG. 11A illustrates a block diagram of an electrical system for an RDA1102, according to some embodiments. The RDA 1102 may include one ormore processors 1104. The processor(s) 1104 may include—or may becommunicatively coupled to—a memory device that stores a set ofinstructions that causes the processor(s) 1104 to perform operationsthat collect sensor data, communicate with a ballistic computer, and/ordisplay text and/or symbols on the optical components of the RDA 1102.In some embodiments, the RDA 1102 may include a ballistic computer 1130as part of the processor(s) 1104, or as a separate processor (notshown). In other embodiments, a ballistic computer may be provided by anexternal device, such as a Kestrel® device. Communication with theexternal ballistic computer may be transmitted through a physicalconnector 1108 and/or through a wireless communications module 1114. Thewireless communications module 1114 may include a Wi-Fitransmitter/receiver, a Bluetooth transmitter/receiver, and/or atransmitter/receiver operating at another radio frequency.

The processor(s) 1104 may receive commands as well as a firing solutionfrom the ballistic computer 1130. The RDA 1102 may also include a symbolgenerator 1106 that can accept a set of commands to generate vectorgraphics on the RDA optical display interface 1110. As described above,a beam splitter may be included as one of the optical components of theRDA optical display interface 1110. A portion of the light receivedthrough the beam splitter may be directed into a daylight sensor 1112.Measurements from the daylight sensor 1112 can be fed into theprocessor(s) 1104 in order to dynamically adjust the brightness of thegraphics displayed through the rifle scope on the RDA. For example,against a white background in daylight, the brightness of the displaycan be dynamically and automatically adjusted to be brighter. Incontrast, against a dark background or at night, the brightness of thedisplay can be dynamically and automatically adjusted to be dimmer.

The RDA 1102 may include one or more sensors that are communicativelycoupled to the processor(s) 1104 through a communication bus 1116. Insome embodiments, the communication bus 1116 may comprise an I²C bus. Insome embodiments, the RDA 1102 may include a magnetic heading sensor1118 to measure an azimuth angle of the rifle. In some embodiments, theRDA 1102 may include a gravitational tilt sensor 1120 to measure thetilt and/or rotation angle of the rifle with respect to a gravitationalvector. In some embodiments, the RDA 1102 may also include a laserrangefinder 1122. The laser rangefinder may be an integrated part of theRDA optical display interface 1110. Alternatively, the laser rangefinder1122 can be an external sensor rather than an integrated part of the RDA1102. Similarly, a windage sensor 1124 may be an integrated part of theRDA 1102 and/or may be externally provided. Sensors that are externallyprovided may communicate directly with an external ballistic computer,and/or may communicate with the processor(s) 1104 through the connector1108.

FIG. 11B illustrates a block diagram of a second electrical system foran RDA, according to some embodiments. The electrical system of FIG. 11Bmay be considered a specific implementation of the more genericelectrical system of FIG. 11A. In order to provide an enablingdisclosure, specific part numbers may be provided for the majorcomponents in FIG. 11B. However, these part numbers are merely exemplaryand not meant to be limiting. One having skill in the art would readilyunderstand that many other specific parts may be used that provide thesame or similar functionality.

A keypad 1132 may function as the RDA control described above forcalibrating and operating the user interface of the RDA. An externalconnector 1134 can receive serial communications (e.g., RS-232) fromexternal components, such as a ballistic computer, a windage sensor, alaser rangefinder, and/or the like. The external connector 1134 can alsoreceive instructions to program a microprocessor 1138 (e.g., LPC1347)through a serial line driver/receiver 1136 (e.g., ADM3101). Power may beprovided externally through the external connector 1134 and/or through auser-replaceable battery 1142 (e.g., CR-123A). In addition to receivingcommunications through the external connector 1134, the RDA can receivecommunications through a wireless connection, such as a Bluetooth®antenna 1150.

Sensors integrated into the RDA may include a linear accelerometer formeasuring the tilt of the RDA with respect to a gravity vector and/or amagnetic heading sensor 1140. In some embodiments, these two sensors canbe integrated into the same package (e.g., LSM9DS0). The RDA may alsoinclude a daylight sensor 1132 that is configured to receive light froma beam splitter in the optical components of the RDA. For example, thedaylight sensor 1132 may include a photodiode that generates a responsethat is proportional to the amount of light received through the opticsof the RDA to automatically adjust the brightness of the display. Inorder to generate the text and/or symbols displayed by the RDA, an LCOSDisplay 1148 (e.g., SYL2271), an LCD controller processor 1144 (e.g.,SYA1231), and a Graphics Processing Unit (e.g., FT810) may also beincluded.

FIG. 12 illustrates a flowchart of a method for displaying firingsolutions using a display adapter that is configured to mount to a frameof a rifle scope, according to some embodiments. The method may includesending position information of the RDA from the RDA to a ballisticcomputer (1202). In some embodiments, the position information mayinclude a tilt angle of the RDA as measured by a linear accelerometer orother gravitational tilt sensor. The position information may alsoinclude a magnetic heading.

The method may also include receiving, at the RDA, a firing solutionfrom the ballistic computer (1204). The firing solution may include awindage adjustment and/or an elevation adjustment. The method mayfurther include displaying a targeting reticle on a display device ofthe RDA (1206). In some embodiments, the targeting reticle may bedisplayed relative to a crosshair of the rifle scope according to thefiring solution as described in detail above. Some embodiments may alsodisplay a calculated windage measurement and/or a calculated range to atarget. A graphic may also be displayed that visually indicates aconvergence of a windage calculation algorithm. The graphic may includegraphical elements that visually converge on a center point as thewindage calculation algorithm converges (e.g., FIGS. 8A-8B). Thetargeting reticle may be displayed such that the targeting reticleoverlays an image visible through the eyepiece of the rifle scope. Thus,a shooter looking through the rifle scope may see the normal image ofthe targeting area along with the text in symbols projected by the RDAthrough the rifle scope.

In order to calibrate the RDA, a control pad may be provided throughwhich inputs can be received. Inputs received through the control can beused to visually align the crosshair of the rifle scope with a crosshairprojected by the RDA. For example, such inputs can rotate, horizontallyshift and/or vertically shift the crosshair projected by the RDArelative to the crosshair of the rifle scope.

It should be appreciated that the specific steps illustrated in FIG. 12provide particular methods of displaying information through an RDAaccording to various embodiments of the present invention. Othersequences of steps may also be performed according to alternativeembodiments. For example, alternative embodiments of the presentinvention may perform the steps outlined above in a different order.Moreover, the individual steps illustrated in FIG. 12 may includemultiple sub-steps that may be performed in various sequences asappropriate to the individual step. Furthermore, additional steps may beadded or removed depending on the particular applications. One ofordinary skill in the art would recognize many variations,modifications, and alternatives.

Rifle Scope Display Mount

The rifle scope display adapter (RDA) described above is designed toprovide an accurate targeting solution on a display through a riflescope to a shooter such that the shooter can keep their eyes on thetarget at all times. In order to guarantee the accuracy of the virtualtargeting reticle of the firing solution, the RDA must be securelyaffixed to the rifle scope such that the RDA does not shift, rotate, ormove between shots. However, the RDA should not be permanently securedto the rifle scope because the rifle scope itself is a modular unit, onethat may be replaced, calibrated, and/or damaged. Thus, not only mustthe RDA be securely affixed to the rifle scope, it also should beremovable. Finally, hundreds of different long-range rifle scopes areavailable, each having different ranges, precision manufacturingrequirements, and uses. Therefore, a mount assembly used to secure theRDA to the scope should be able to accommodate all of the availabledifferent scope diameters.

Prior to this disclosure, accessories mounted in front of the riflescope on a rifle could be attached using one of two methods. First, manyrifle scopes include a threaded section on the interior of the scopebody in front of the front lens. Accessories can be screwed into thefront of the scope using these interior threads. For example, alightweight accessory known as a “flash kill” can be screwed into thefront of a rifle scope in order to block light reflections off the frontof the scope lens that could give away the position of the shooter.While these threads may be used to secure lightweight accessories,heavier accessories, such as the RDA described above, are too heavy tobe secured using these threads alone. Furthermore, the shock generatedby high-powered rifles is often sufficient to gradually loosen anaccessory from these threads. Even a few millimeters of rotation of theRDA would skew the calibrated targeting image and result in aninaccurate virtual targeting reticle. Second, some rifle accessories maybe mounted in front of the scope on a “Picatinny” or other rail system.While affixing an accessory to the rail may be secure, small amounts ofplay in the rail assembly, the mounting fixture, the scope mount, andthe accessory, may add up to an unacceptable amount of movement betweenthe accessory and the scope between shots.

In order to solve these and many other problems, the embodimentsdescribed herein present a method of mounting the RDA directly to thefront of the scope in a secure and removable manner. These embodimentsguarantee that the RDA does not move, rotate, or shift between shots ofhigh-powered rifles. These embodiments also allow a common RDA projectordisplay to be mounted to differently sized rifle scopes having variablediameters. These embodiments also make certain that the RDA is seatedproperly against the scope so that the projected image is not skewedthrough the scope lens.

A first aspect of these embodiments provides a threaded ring that can bescrewed into the interior threads of the existing scope body. Thethreaded ring ensures that the RDA projector display is seatedperpendicular to the optical path of the scope by pulling the RDA flushagainst the front of the scope body. A second aspect of theseembodiments keeps the threaded ring on the interior of the scope bodyfrom loosening by providing radial pressure directed inwards towards thebody of the scope via a second ring around the exterior of the scope.This radial pressure is exerted using the second ring on the outside ofthe scope body.

FIGS. 13A-13D illustrate various views of one embodiment of an RDAassembly, according to some embodiments. The assembly may be comprisedof a plurality of individual components used to mate the RDA commondisplay projector (“display projector”) 1312 to a scope body 1302. Thedisplay projector 1312 may be provided in a single size, and theremaining components of the assembly can include interchangeable membersof variable sizes to accommodate scope bodies with different diameters.Therefore, only a single display projector 1312—which includes theoptical components, electrical components and connectors, controllers,sensors, and processors described in detail above—needs to be designedand manufactured, and the remaining components in the assembly can beused to secure the display projector 1312 to virtually any size of riflescope.

It will be understood that the specific components in the assemblydepicted in FIGS. 13A-13D are merely exemplary and not meant to belimiting. Functionally, these components provide the two aspectsdescribed above: (1) a first ring that mates with the threads on theinterior of the scope body 1302 and secures the display projector 1312flush with the front of the scope body 1302; and (2) a second ring thatexerts radial compressive force against the exterior of the scope body1302. In light of this disclosure and these two aspects, one havingskill in the art could alter the assembly components described belowinto alternate geometries in order to provide the same functionality.Such modifications are within the scope of this invention.

In some embodiments, the assembly is comprised of an outer tighteningring (“outer ring”) 1304, a collet 1306, a spacer adapter (“spacer”)1308, and an inner fingertip grip filter thread tightening ring (“innerring”) 1310. To describe the functionality of each of these individualcomponents, FIGS. 14-17 each depict a single component apart from theassembly. In the accompanying description below, reference will be madeback to FIGS. 13A-13D to illustrate how the components are assembled toattach the display projector 1312 to the scope body 1302.

Beginning with the inner ring 1310, FIG. 14 illustrates an outside view1402 and an inside view 1404 of the inner ring 1310, according to someembodiments. A portion of the display projector 1312 is also illustratedin order to show how the inner ring 1310 seats within the displayprojector 1312. The inner ring 1310 may be comprised of two rings ofdifferent diameters. A threaded ring 1404 may include screw threads (notshown for clarity) on the outside surface of the threaded ring 1404. Agrip ring 1406 may include a grippable surface on the outside surface ofthe grip ring 1406. The grip surface may include a diamond pattern,small ridges and/or valleys, a scored surface, a sandpaper-like surface,and so forth. The grip ring 1406 and the threaded ring 1404 may bemanufactured from a single block of material (e.g., machined from asingle piece of aluminum), or they may be manufactured separately andjoined together. In either case, the grip ring 1406 and the threadedring 1404 will turn in unison as the grip ring 1406 is rotated.

The grip ring 1406 may be a constant diameter regardless of the scopediameter. The grip ring 1406 may include a flange 1410 that is sized tomate with a corresponding groove or recess in the display projector1312. During assembly, the flange 1410 of the grip ring 1406 may beseated within the corresponding groove or recess in the displayprojector 1312 such that the grip ring 1406 can rotate freely radiallyaround its center diameter. However, the corresponding groove or recessin the display projector 1312 prevents the inner ring 1310 from shiftingor moving perpendicular to the center diameter of the inner ring 1310.

The threaded ring 1404 may be manufactured in varying diameters toaccommodate the varying diameters of different scope bodies. Forexample, some embodiments of the threaded ring 1404 may be sized toaccommodate the interior diameter and threads of a scope body of aLeupold® MK4 ER/T 50 mm 6.5-20×50 mm Army M2010 scope. Other embodimentsof the threaded ring 1404 may be sized to accommodate a Leupold® USSOCOMECOS-O MK6 3-18×44 mm scope, or a Schmidt & Bender® 5-25×56 mm PMIIUSSOCOM PSR scope. In addition to these exemplary scope models, and inlight of this disclosure, one having skill in the art would be able tomeasure the internal diameter and thread spacing of any scope and designa threaded ring 1404 accordingly.

After the inner ring 1310 is seated in the display projector 1312, thegrip ring 1406 is accessible to a user through an opening 1412 in thebody of the display projector 1312. Although not shown in the outsideview 1402 or in FIGS. 13A-13C, the dashed lines of the inside view 1404show a ring 1408 of the display projector 1312 that extends over theinner ring 1310. The user is able to rotate the inner ring 1310 bygripping the grip ring 1406 through the opening 1412, which extendsaround at least a portion of the ring 1408. Thus, the inner ring can berotated through the opening 1412 of the display projector 1312 in orderto mate the threads of the threaded ring 1404 with the threads of theinside of the scope body 1302. The ring 1408 of the display projector1312 may include threads on the interior (not shown for clarity) of thering 1408 in order to mate with the spacer 1308 as described in greaterdetail below.

FIGS. 13A-D and FIGS. 14-17 illustrate components sized for a 50 mmscope body. To illustrate how the size of the assembly components canchange in order to accommodate both larger and smaller sizes, FIG. 18illustrates a 56 mm scope body, and FIG. 19 illustrates a 44 mm scopebody. Note that the threaded ring of the inner ring 1310 in FIG. 18 islarger to accommodate the 56 mm scope, and the threaded ring of theinner ring 1310 in FIG. 19 is smaller to accommodate the 44 mm scope. Incontrast, the grip ring for all three scope sizes can remain the same.

FIG. 15 illustrates an outside view 1502 and an inside view 1504 of thespacer 1308, according to some embodiments. After seating the inner ring1310 in the display projector 1312, the spacer 1308 can be screwed intothe display projector 1312 to hold the inner ring 1310 in place. Likethe inner ring 1310, the spacer can be functionally divided into twodifferent external diameters, namely a large ring 1508 disposed closerto the scope body 1302, and a small ring 1506 disposed closer to thedisplay projector 1312. The small ring 1506 may include threads (notshown for clarity) on the external surface of the small ring 1506 inorder to mate with the corresponding threads on the inner surface of thering 1408 of the display projector 1312. Similarly, the large ring 1508may include threads (not shown for clarity) on the external surface ofthe large ring 1508 for mating with corresponding threads on the outerring 1304 as described in greater detail below.

After screwing the spacer 1308 into the display projector 1312, theinner ring 1310 will be held in place such that it can rotate around itscenter axis, but cannot shift off that center axis or along the centeraxis. As illustrated in FIG. 13C, a surface 1510 of the small ring 1506will seat against the side of the grip ring 1406 of the inner ring 1310,holding the inner ring 1310 in place. The threaded ring 1404 of theinner ring 1310 will extend through the opening inside the surface 1510of the small ring 1506 to screw into the inside threads of the scopebody. An opposite surface 1514 of the small ring 1506 will seat againstthe front of the scope body 1302. Therefore, when the spacer 1308 andthe inner ring 1310 are assembled with the display projector 1312, theinner ring 1310 can be screwed into the inside threads of the scope body1302 until the opposite surface 1514 of the spacer 1308 is flush withthe front of the scope body 1302. This ensures that the optical displayelements of the display projector 1312 are parallel with the scope lens,or perpendicular to the center axis of the scope. Thus, the inner ring1310 and the spacer 1308 provide for the first aspect described abovefor mounting the RDA to the scope body 1302 by providing a threadedattachment that can be screwed into the front of the scope body 1302 toensure that the optical components of the display projector 1312 are notskewed in relation to the scope lens.

In some embodiments, the spacer 1308 may also help provide for thesecond aspect described above for mounting the RDA to the scope body1302 by translating radial pressure against the external surface of thescope body 1302. As will be described in greater detail below, theinterior of the spacer 1308 includes a sloped surface 1512 that willcause a compressible ring, such as the collet 1306, to be compressedagainst the scope body 1302 as the compressible ring and the spacer 1308move towards each other. The outside diameters of the large ring 1508and the small ring 1506 for the spacer 1308 may be the same fordifferent sized scopes. However, because the outside diameter of eachscope will change, the diameter of the compressible ring will also needto change to match the outside diameter of each scope body 1302.Therefore, the interior radius of the spacer 1308 with the slopedsurface 1512 will grow or shrink based on the diameter of the scope andthe compressible ring. The angle of the sloped surface 1512 need notchange.

FIG. 16 illustrates a collet 1306, according to some embodiments. Asdescribed above, a compressible ring can be used to provide radialpressure against the external surface of the scope body 1302. In someembodiments, the collet 1306 can be used to translate a horizontalmotion of the collet 1306 being pressed against the sloped surface 1512of the spacer 1308 into a radial compression. By compressing the collet1306 against the outside surface of the scope body 1302, the RDA will beheld securely in position, even in the high-shock environment of ahigh-powered rifle. The collet 1306 effectively prevents rotation of theRDA (i.e., unscrewing from the threads on the interior of the scope body1302) that would otherwise occur.

The collet 1306 may include a series of interdigitated fingers 1602spaced evenly around its circumference. The interdigitated fingers 1602allow the collet 1306 to be compressed radially, such that an internaldiameter of the collet 1306 is reduced. As the sloped surface 1604 ispressed into the spacer 1308, the collet 1306 is radially compressed.Specifically, the sloped surface 1502 of the spacer 1308 presses againstthe sloped surface 1604 of the collet 1306 in order to compress thecollet 1306 against the outside surface of the scope body 1302.

In order to accommodate scopes of varying sizes, the diameter of theportion of the collet 1306 that includes the sloped surface 1604 cangrow or shrink. The collet 1306 also includes a flange 1606 on theleft-hand side in FIG. 16. The flange 1606 is seated against the outerring 1304 as described in greater detail below. The outer ring 1304presses against the flange 1606 in order to press the collet 1306 intothe spacer 1308. As the diameter of the portion of the collet thatincludes the sloped surface 1604 grows or shrinks, the length of theflange 1608 can strength or grow respectively. The outer diameter of theflange 1606 may remain constant while the length of the flange 1606 (andthe inner diameter) grows or shrinks to accommodate the changing radiusof the portion of the collet 1306 that includes the sloped surface 1604.FIG. 18 illustrates a collet 1306 for a larger scope body with a largerdiameter for the portion with the sloped surface 1604, where the flange1606 is shorter. In contrast, FIG. 19 illustrates a collet 1306 for asmaller scope body with a smaller diameter for the portion with thesloped surface 1604, where the flange 1606 is longer. The angle of thesloped surface 1604 need not change.

FIG. 17 illustrates an outside view 1702 and an inside view 1704 of anouter ring 1304, according to some embodiments. The outer ring 1304 mayhave a constant outside diameter regardless of the diameter of the scopebody 1302. Similarly, an interior diameter of the outer ring 1304 mayalso have a constant value in order to mate with the outer diameter ofthe spacer 1308. The surface 1708 of the interior diameter of the outerring 1308 may include threads (not shown for clarity) such that outerring 1308 can be screwed onto the threads on the outer surface of thelarge ring 1508 of the spacer 1308.

In order to adjust for different-sized scope bodies, a flange 1706 onthe left-hand side of the outer ring 1304 can be manufactured longer orshorter depending on the diameter of the scope body. The flange 1706 canbe sized such that the internal opening created by the flange issubstantially the same as the outside diameter of the scope body 1302,such that there is no gap between the scope body 1302 and the flange1706. The internal surface of the flange 1706 may be approximately thesame length as the flange 1606 on the collet 1306. The flange 1606 ofthe collet 1306 will be flush with the internal surface of the flange1706 of the outer ring 1304.

In order to attach the spacer 1308, inner ring 1310, and displayprojector 1312 assembly to the front of the scope body 1302, the outerring 1304 can be slipped over the scope body 1302. Next, the collet 1306can be similarly slipped over the scope body 1302. The spacer 1308 canthen be placed against the scope body 1302, and the inner ring 1310 canbe rotated such that the threads of the inner ring 1310 engage with thethreads on the internal surface of the scope body 1302. The inner ring1310 can be rotated until the spacer 1308 is flush with the front of thescope body 1302. Next, the collet 1306 can be moved forward on the scopebody 1302 into the spacer 1308. The outer ring 1304 can then besimilarly moved forward, and the outer ring 1304 can be rotated suchthat the threads on the internal surface of the outer ring 1304 engagewith the corresponding threads on the spacer 1308. As the outer ring1304 is screwed onto the spacer 1308, the flange 1706 of the outer ring1304 will gradually press the collet 1306 further into the spacer. Thesloped surfaces of the spacer 1306 and the collet 1308 will pressagainst each other and cause the collet 1306 to compress against thescope body 1302. The outer ring 1304 can be rotated until it is tight,indicating that the collet 1306 is compressed as much as possibleagainst the scope body 1302, and therefore providing a maximum amount ofradial pressure against the scope body 1302 to prevent the displayprojector 1312 from moving relative to the scope body 1302.

FIG. 20 illustrates a flowchart of a method for securing an RDA to ascope body, according to some embodiments. The method may includescrewing a first ring into corresponding threads on an internal surfaceof the scope body (2002). For example, the inner ring 1310 describedabove may be screwed into the threads of the inner surface of the scopebody 1302. This may provide a first attachment mechanism. The method mayalso include inserting the scope body into a second ring (2004). Forexample, the scope body may be inserted into the outer ring 1304 and/orthe collet 1306 as described above. The method may also include, usingthe second ring, providing compressive, radial pressure against thescope body (2006). For example, the outer ring 1304 and/or the collet1306 may be used to compress the collet 1306 to provide compressive,radial pressure against the scope body. This may provide a secondattachment mechanism, thereby holding the RDA securely in place relativeto the scope body.

As described above, the inner ring 1310 and the spacer 1308 are securedto the display projector 1312. These three components can be heldtogether by a thread pin inserted through the body of the displayprojector 1312 into the body of the spacer 1308. Turning back to FIG.13C, a thread pin 1320 can be inserted such that the spacer 1308 is notallowed to rotate relative to the display projector 1312. Thus, in orderto remove the RDA from the scope body 1302, the outer ring 1304 cansimply be unscrewed from the spacer 1308. The outer ring 1304 can thenbe moved backwards off the spacer 1308, and thereby relieve the forwardpressure on the collet 1306. As forward pressure is relieved from thecollet 1306, the collet will expand and move backwards towards the outerring 1304, thereby releasing the radial pressure on the external surfaceof the scope body 1302. The inner ring 1310 can then be rotated tounscrew the spacer 1308, inner ring 1310, and display projector 1312assembly from the front of the scope body 1302. When the thread pin 1320is inserted, the spacer 1308, inner ring 1310, and display projector1312 assembly can act as a single unit that does not need to beassembled/disassembled every time the RDA is removed from the scope body1302.

It can be noted that the above, embodiments of the RDA may be modifiedto address manufacturing and/or other concerns. For example, snipershooters may require extremely high image quality from rifle scope's toidentify targets and spot their shots. Furthermore, it may be difficultto manufacture a transmissive light bar that meets both image qualityand cost requirements. For example, in reference to FIG. 1B, due to thedifference in the index of refraction of the transmissive light bar 55and the open air surrounding it, it may produce an optical blur to auser looking through the eyepiece of the rifle scope. The transmissivelight bar 55 may further have to meet a critical angle requirementbetween front and back surfaces (surfaces through which light travelingtoward the objective lens of the rifle scope is transmitted) to minimizerefractive optical distortions. Meeting these requirements can oftenincrease the cost of manufacture for the transmissive light bar. Assuch, embodiments of the RDA may be modified to include a polarizedwindow to reduce costs and increase image quality.

FIG. 21 is a perspective view of an RDA 2100 having a polarized window2110, according to an embodiment. It should be noted, however, that thisis a simplified diagram provided for illustrative purposes. Thepolarized window 2110, as noted below, can include various types ofmounting fixtures, protective covering, and other features notillustrated. To be clear, although item 2110 of FIG. 21 is described asa “polarized window” only a portion of the polarized window 2110 mayactually include a polarized coating, as described below. Inembodiments, such as these, the remaining portion of the polarizedwindow 2110 might not be polarized.

Similar to the RDA 40 illustrated in FIG. 1B, the RDA 2100 of FIG. 21,can include an annulus 2120, as well as a casing 2160 on which aparallax adjustment knob 2130, button interface 2140, and connectionport 2150 may be disposed. Here, however, the RDA 2100 further includesa polarized window 2110 that replaces the transmissive light bar 55 andpolarized beam splitter 56 of the RDA 40 of FIG. 1B. Other features ofthe RDA 2100 of FIG. 21 may be the same or similar to features of theRDA 40 of FIG. 1B.

Similar to the light bar 55 it replaces, the polarized window 2110 is apolarized transmissive-reflective optical element that can both reflectpolarized light emitted from optics in the casing 2160 into theobjective lens of the rifle scope onto which the RDA 2100 is mounted,and transmit other light (e.g., light of a scene viewable from aneyepiece of the rifle scope), incident on the polarized window 2110,that is traveling toward the objective lens. To do so, the polarizedwindow 2110 may comprise a transmissive material, such as glass, whichmay be chosen based on transmissive properties, structural integrity,manufacturing concerns, and/or other factors. For example, in someembodiments, the polarized window may comprise BK7 glass or anotherglass, having similar properties. The polarized window 2110 may haveanti-reflective and/or coatings, as desired, which may depend on theapplication of the RDA 2100. Additionally, the polarized window 2110 maybe substantially flat to help minimize refractive optical distortions.The thickness of the polarized window 2110 may vary, depending on thetype of material and desired optical properties. That said, thethickness of the polarized window 2110 may have a minimal effect on itsoptical properties. Thus, the primary concern for determining thethickness in some embodiments may be whether the polarized window 2110is sufficiently thick to handle gun shock.

To reflect polarized light emitted from optics within the casing 2160(which may be generated and transmitted within the casing 2160 using thecomponents (e.g., display unit and/or optical subassembly) such as thosedescribed in the embodiments above), the polarized window 2110 mayinclude a polarized coating 2115. As illustrated, in some embodimentsthe polarized coating 2115 may be disposed on only a portion of asurface (e.g., inner surface closest to the casing 2160) of thepolarized window 2110 to help minimize loss of light transmitted by thepolarized window 2110. In some embodiments, for example, the portion ofthe surface of the polarized window 2110 on which the polarized coating2115 is disposed may comprise only a small percentage (e.g., 20%, 10%,or less) of the total area of the surface. In one example, the area ofthe polarized coating 2115 may be limited to only a 15×15 mm area on thepolarized window 2110. For a 60 mm objective, and given thetransmissivity of the polarized coating 2115, this would result in lessthan a 2% light loss overall. It will be understood, however, thatembodiments may vary in the size of area of the polarized coating 2115,as well as types of polarized coating.

As previously indicated, optical components within the casing 2160 maybe similar to embodiments described above (e.g., as illustrated in FIG.1A). However, because the polarized window 210 transmissive light bar ofprevious embodiments had a “folded” design, in which, as illustrated inFIG. 3, light traveled through the transmissive light bar and reflectedoff of a spherical mirror 58 before being directed into the objectivelens of the rifle scope by the polarized beam splitter 56, the opticalcomponents within the casing 2160 may need to be adjusted to maintainthe original focal length. (In some embodiments, this focal length was108 mm, although alternative embodiments may have longer or shorterfocal lengths.)

As illustrated in FIG. 21, the polarized window 2110 is angled in orderto direct light from the optical components within the casing 2160 intothe objective lens of the rifle scope onto which the RDA 2100 ismounted, at (according to some embodiments) an angle substantiallynormal to the surface of the objective lens. This is showing more detailin FIG. 22.

FIG. 22 is a diagram of the RDA 2100 attached to a rifle scope 2200showing light paths similar to those in FIGS. 2C and 2D. As can be seen,the polarized window 2110 transmits light from a scene and reflects LEDlight from the LED housed in the casing 2160. As noted above, thepolarized window 2110 can direct the LED light into the objective lens2210 added on an angle substantially normal to the objective lens 2210.

It can be noted that, although the angle of LED light incident on thepolarized window 2110 is approximately a 45° angle, the angle can bechanged, depending on desired functionality. That is, in someembodiments, the angles at which the LED light leaves the casing 2160and reflects off of the polarized window 2110 can be modified to, forinstance, allow the angle 2220 between the polarized window 2110 and theobjective lens 2210 to be reduced. This can, in turn, allow thepolarized window 2110 (and overall RDA 2100) to have a lower profilefrom the front of the rifle scope 2200.

Turning again to FIG. 21, the illustration does not show any means ofprotection for the polarized window 2110, but alternative embodimentsmay include such protection. Depending on desired functionality, thepolarized window 2110 may be mounted or otherwise fastened to theannulus 2120 in a permanent manner (e.g., at manufacture) to ensure theproper angles between the polarized window 2110 and the casing 2160 aremaintained. In some embodiments, however, components, such as the casing2160, polarized window 2110, and/or components within the casing 2160may be movable to allow calibration in the field. In any case,embodiments may additionally or alternatively include any of a varietyof forms of protection for the polarized window 2110 to protect it fromimpact, weather, and/or other things that could damage the polarizedwindow 2110 and/or degrade its performance. In some embodiments, forexample, in additional glass and/or plastic cover (not shown) may extendout from the annulus 2120, encasing the polarized window and protectivecover. The features of such an encasing (thickness, material, shape,etc.) may be adjusted to reduce light loss, increase strength, minimizeoptical distortions, etc. Additionally or alternatively, the encasingmay be removable, thereby eliminating any negative effects that apermanent encasing would have, while enabling the polarized window 2110to be protected when the RDA 2100 is not in use.

It can be noted that the size and shape of the polarized window 2110 canbe adjusted to reduce the amount of optical distortions. Unlike thetransmissive light bar in previous embodiments, for example, the sizeand the shape of the polarized window 2110 may be such that it occupiessubstantially all of the field of view of the rifle scope, to minimizeany refractive optical distortions that may occur near the edges of thepolarized window 2110.

FIG. 23 is a ray tracing diagram showing example paths of light rayswithin an embodiment of an RDA having a polarized window, such as theembodiment illustrated in FIGS. 21 and 22. Components similar to thosein FIG. 3 are labeled similarly. As with FIG. 3, FIG. 23 omitsillustrating rays of light emitted by the LED 41 and the reflection ofthis light towards the LCOS 39, for clarity of the illustration. Rather,the rays shown in the drawing are intended to illustrate the path oflight only after its reflection at the LCOS 39. Additionally, the lightpath through the rifle scope is omitted in FIG. 23.

Although not shown, the LED 52 emits light towards a polarized beamsplitter 51 that is angled 45 degrees relative to the path of the light.Prior to reaching the polarized beam splitter 51, the light can bepolarized by the polarizer 53. Optionally, the light may be diffused bya diffuser prior to reaching the polarized beam splitter 51 (e.g., thediffuser is disposed between the LED 52 and the polarized beam splitter51), before or after the polarizer 53. In some embodiments the polarizer53 may also act as a diffuser.

Also, a wire grid polarizer (not shown) can be used to polarize thelight in such a way that it will be reflected at the polarized beamsplitter 51. Because of the polarity of the light incident on thepolarized beam splitter 51, the beam splitter reflects the light towardsthe LCOS 39.

The processing circuitry 41 generates electrical control signals thatcause a combination of LCOS reflective pixel elements to reflect theincident light. The LCOS 39 also reverses the polarity of the light thatit reflects. The light reflected by the LCOS 39 is reflected backtowards the polarized beam splitter 51, where it is transmitted as aresult of the polarity reversal imparted by the LCOS 39.

After being transmitted by the polarized beam splitter 51, the lightpropagates towards a moving telephoto lens assembly 61 that providesparallax adjustment. The light is divergently refracted by the telephotolens assembly 61 in a manner that provides compensation sufficient toprevent parallax from affecting the rifle scope view.

Subsequent to being transmitted by the telephoto lens assembly 61, thelight is incident on a reflective element 54 that is disposed at anangle that is approximately 45 degrees from parallel to the path of thelight (however, as noted above, alternative embodiments may have thereflective element 54 at a different angle, enabling the angle of thepolarized window 2310 to be changed. The reflection of the light by thereflective element 54 causes an approximately 90 degree change indirection of the light. Following reflection, the light travels througha collimating lens assembly 2320 toward the polarized window 2310. Aspreviously noted, the light may travel toward and reflect off of aportion of the polarized window 2310 having a polarized coating.

The polarized window 2310 is approximately centered with respect to thecircular aperture (not shown in FIG. 23) of the annulus. By beingcentered with respect to the circular aperture, the polarized window2310 can be disposed so that it will coincide with an extended opticalaxis (not explicitly labeled) of the rifle scope to which the RDA iscoupled. That is, the polarized window 2310 can be disposed directly infront of the center of the rifle scope objective lens (not shown in FIG.23).

As a result of the polarity of the light when reflected at reflectiveelement 54, the light is reflected by the polarized window 2310, causinga 90 degree change in direction (again, this may be a different angle inalternative embodiments). As can be seen in FIG. 23, the light rays areeffectively collimated by the collimating lens assembly 2320. Thesecollimated light rays are then incident at the objective lens of therifle scope (not shown), which transmits and refracts the rays towardsthe optical eyepiece in the manner depicted in FIG. 2D. It can be notedthat, depending on desired functionality, the configuration of thetelephoto lens assembly 61 and/or collimating lens assembly 2320relative to the reflective element 54, may vary, depending on desiredfunctionality. In some embodiments, the collimating lens assembly 2320may be situated by the telephoto lens assembly 61, such that the lighttravels through the collimating lens assembly 2320 prior to reflectingoff of the reflective element 54. In other embodiments, collimation mayoccur using additional or alternative optical elements (which mayinclude the reflective element 54, for example).

In the foregoing description, for the purposes of explanation, numerousspecific details were set forth in order to provide a thoroughunderstanding of various embodiments of the present invention. It willbe apparent, however, to one skilled in the art that embodiments of thepresent invention may be practiced without some of these specificdetails. In other instances, well-known structures and devices are shownin block diagram form.

The foregoing description provides exemplary embodiments only, and isnot intended to limit the scope, applicability, or configuration of thedisclosure. Rather, the foregoing description of the exemplaryembodiments will provide those skilled in the art with an enablingdescription for implementing an exemplary embodiment. It should beunderstood that various changes may be made in the function andarrangement of elements without departing from the spirit and scope ofthe invention as set forth in the appended claims.

Specific details are given in the foregoing description to provide athorough understanding of the embodiments. However, it will beunderstood by one of ordinary skill in the art that the embodiments maybe practiced without these specific details. For example, circuits,systems, networks, processes, and other components may have been shownas components in block diagram form in order not to obscure theembodiments in unnecessary detail. In other instances, well-knowncircuits, processes, algorithms, structures, and techniques may havebeen shown without unnecessary detail in order to avoid obscuring theembodiments.

Also, it is noted that individual embodiments may have beeen describedas a process which is depicted as a flowchart, a flow diagram, a dataflow diagram, a structure diagram, or a block diagram. Although aflowchart may have described the operations as a sequential process,many of the operations can be performed in parallel or concurrently. Inaddition, the order of the operations may be re-arranged. A process isterminated when its operations are completed, but could have additionalsteps not included in a figure. A process may correspond to a method, afunction, a procedure, a subroutine, a subprogram, etc. When a processcorresponds to a function, its termination can correspond to a return ofthe function to the calling function or the main function.

The term “computer-readable medium” includes, but is not limited to,portable or fixed storage devices, optical storage devices, wirelesschannels and various other mediums capable of storing, containing, orcarrying instruction(s) and/or data. A code segment ormachine-executable instructions may represent a procedure, a function, asubprogram, a program, a routine, a subroutine, a module, a softwarepackage, a class, or any combination of instructions, data structures,or program statements. A code segment may be coupled to another codesegment or a hardware circuit by passing and/or receiving information,data, arguments, parameters, or memory contents. Information, arguments,parameters, data, etc., may be passed, forwarded, or transmitted via anysuitable means including memory sharing, message passing, token passing,network transmission, etc.

Furthermore, embodiments may be implemented by hardware, software,firmware, middleware, microcode, hardware description languages, or anycombination thereof. When implemented in software, firmware, middlewareor microcode, the program code or code segments to perform the necessarytasks may be stored in a machine readable medium. A processor(s) mayperform the necessary tasks.

In the foregoing specification, aspects of the invention are describedwith reference to specific embodiments thereof, but those skilled in theart will recognize that the invention is not limited thereto. Variousfeatures and aspects of the above-described invention may be usedindividually or jointly. Further, embodiments can be utilized in anynumber of environments and applications beyond those described hereinwithout departing from the broader spirit and scope of thespecification. The specification and drawings are, accordingly, to beregarded as illustrative rather than restrictive.

Additionally, for the purposes of illustration, methods were describedin a particular order. It should be appreciated that in alternateembodiments, the methods may be performed in a different order than thatdescribed. It should also be appreciated that the methods describedabove may be performed by hardware components or may be embodied insequences of machine-executable instructions, which may be used to causea machine, such as a general-purpose or special-purpose processor orlogic circuits programmed with the instructions to perform the methods.These machine-executable instructions may be stored on one or moremachine readable mediums, such as CD-ROMs or other type of opticaldisks, floppy diskettes, ROMs, RAMs, EPROMs, EEPROMs, magnetic oroptical cards, flash memory, or other types of machine-readable mediumssuitable for storing electronic instructions. Alternatively, the methodsmay be performed by a combination of hardware and software.

What is claimed is:
 1. A rifle scope display adapter comprising: a bodycoupleable with a rifle scope and having: a display unit disposed in acasing; an optical subassembly disposed in the casing and including alens and a reflective element, the optical subassembly configured todirect light from the display unit toward a polarizedtransmissive-reflective optical element; and the polarizedtransmissive-reflective optical element coupled with the casing suchthat, when the body of the rifle scope display adapter is coupled withthe rifle scope, the polarized transmissive-reflective optical elementis disposed in front of an objective lens of the rifle scope in a mannerto: reflect the light from the display unit toward the objective lens ofthe rifle scope, and transmit other light incident to the polarizedtransmissive-reflective optical element and traveling toward theobjective lens of the rifle scope.
 2. The rifle scope display adapter ofclaim 1, wherein the polarized transmissive-reflective optical elementcomprises a polarized window.
 3. The rifle scope display adapter ofclaim 1, wherein the polarized transmissive-reflective optical elementis configured to, when the body of the rifle scope display adapter iscoupled with the rifle scope, occupy substantially all of the field ofview of the rifle scope.
 4. The rifle scope display adapter of claim 1,wherein the display unit comprises a liquid crystal on silicon (LCOS).5. The rifle scope display adapter of claim 4, wherein the opticalsubassembly further comprises: a light-emitting element; a polarizingelement configured to polarize light emitted by the light-emittingelement; and a polarized beam splitter configured to: reflect thepolarized light towards the LCOS, and transmit light reflected by theLCOS toward the reflective element, the light reflected by the LCOScomprising the light from the display unit.
 6. The rifle scope displayadapter of claim 5, further comprising a diffuser disposed between alight-emitting element and the polarized beam splitter, the diffuseroperable to diffuse light emitted by the light-emitting element.
 7. Therifle scope display adapter of claim 1, wherein the lens of the opticalsubassembly comprises a movable telephoto lens.
 8. The rifle scopedisplay adapter of claim 1, further comprising a polarized coating ononly a portion of a surface of the polarized transmissive-reflectiveoptical element.
 9. The rifle scope display adapter of claim 8, whereinan area of the portion of the surface comprises less than 20% of thetotal area of the surface.
 10. A method of directing light from adisplay unit toward an objective lens of a rifle scope, the methodcomprising: causing the display unit to display an image; using anoptical subassembly to direct light from the display unit toward apolarized transmissive-reflective optical element, wherein the opticalsubassembly including a lens and a reflective element; and positioningthe polarized transmissive-reflective optical element such that thepolarized transmissive-reflective optical element is disposed in frontof the objective lens of the rifle scope in a manner to: reflect thelight from the display toward the objective lens of the rifle scope, andtransmit other light incident on the polarized transmissive-reflectiveoptical element traveling toward the objective lens of the rifle scope.11. The method of directing light from a display unit toward anobjective lens of a rifle scope of claim 10, wherein the polarizedtransmissive-reflective optical element comprises a polarized window.12. The method of directing light from a display unit toward anobjective lens of a rifle scope of claim 10, wherein the polarizedtransmissive-reflective optical element is configured to, when a riflescope display adapter comprising the polarized transmissive-reflectiveoptical element is coupled with the rifle scope, occupy substantiallyall of the field of view of the rifle scope.
 13. The method of directinglight from a display unit toward an objective lens of a rifle scope ofclaim 10, wherein the display unit comprises a liquid crystal on silicon(LCOS).
 14. The method of directing light from a display unit toward anobjective lens of a rifle scope of claim 13, further comprising: causinga light-emitting element to emit light; polarizing the light emitted bythe light-emitting element; and using a polarized beam splitterconfigured to: reflect the polarized light towards the LCOS, andtransmit light reflected by the LCOS toward the reflective element, thelight reflected by the LCOS comprising the light from the display unit.15. The method of directing light from a display unit toward anobjective lens of a rifle scope of claim 14, further comprisingdiffusing light emitted by the light-emitting element.
 16. The method ofdirecting light from a display unit toward an objective lens of a riflescope of claim 10, wherein the lens of the optical subassembly comprisesa movable telephoto lens.
 17. The method of directing light from adisplay unit toward an objective lens of a rifle scope of claim 10,wherein the polarized transmissive-reflective optical element isconfigured to reflect the light from the display unit using a polarizedcoating on only a portion of a surface of the polarizedtransmissive-reflective optical element.
 18. The method of directinglight from a display unit toward an objective lens of a rifle scope ofclaim 17, wherein an area of the portion of the surface comprises lessthan 20% of the total area of the surface.
 19. A rifle scope displayadapter comprising: a display unit disposed in a casing; an opticalsubassembly disposed in the casing and including an adjustable lens anda reflective element, the optical subassembly configured to direct lightfrom the display unit toward a polarized transmissive-reflective opticalelement; and the polarized transmissive-reflective optical elementcoupled with the casing such that, when the rifle scope display adapteris positioned for use, the polarized transmissive-reflective opticalelement is disposed in front of an objective lens of the rifle scope ina manner to: reflect the light from the display unit toward theobjective lens of the rifle scope, and transmit other light incident tothe polarized transmissive-reflective optical element traveling towardthe objective lens of the rifle scope.
 20. The rifle scope displayadapter of claim 19, wherein the polarized transmissive-reflectiveoptical element comprises a polarized window.